Securing driver requested torque

Abstract

An engine control system comprises a driver axle torque request module (DATRM) and a driver axle torque security module (DATSM). The DATRM determines a pedal torque request based on minimum and maximum scaling torques and a torque scalar. The DATRM determines a raw driver torque request. The DATRM selectively shapes raw driver torque request into a final driver torque request. The DATRM converts the final driver torque request into a first axle torque request. The DATSM selectively diagnoses a fault in the first axle torque request based on a minimum engine torque, the minimum scaling torque, a first comparison of the final driver torque request and the redundant final driver torque request, and a second comparison of the first axle torque request and a redundant axle torque request.

1. An engine control system comprising:
 a driver axle torque request module (DATRM) that determines a pedal torque request based on minimum and maximum scaling torques and a torque scalar, that determines a raw driver torque request, that selectively shapes raw driver torque request into a final driver torque request, and that converts said final driver torque request into a first axle torque request; and 
 a driver axle torque security module (DATSM) that selectively diagnoses a fault in said first axle torque request based on a minimum engine torque, said minimum scaling torque, a first comparison of said final driver torque request and a redundant final driver torque request, and a second comparison of said first axle torque request and a redundant axle torque request. 
 
     
     
       2. The engine control system of  claim 1  wherein said DATSM diagnoses said fault when said minimum scaling torque is one of greater than a predetermined maximum torque limit and less than a predetermined minimum torque limit. 
     
     
       3. The engine control system of  claim 2  wherein said DATSM diagnoses said fault when said minimum torque is one of greater than said maximum torque limit and less than said predetermined minimum torque limit. 
     
     
       4. The engine control system of  claim 1  wherein said DATSM diagnoses said fault when said final driver torque request is one of greater than and less than said redundant final driver torque request. 
     
     
       5. The engine control system of  claim 1  wherein said DATSM sets said redundant final driver torque request equal to one of said final driver torque request and a redundant raw driver torque request before said first comparison is performed. 
     
     
       6. The engine control system of  claim 1  wherein said DATRM limits a rate of shaping of said final driver torque request toward said pedal torque request. 
     
     
       7. The engine control system of  claim 1  wherein said DATSM diagnoses said fault when said redundant axle torque request is greater than a sum of said first axle torque request and a predetermined acceleration torque. 
     
     
       8. The engine control system of  claim 1  wherein, when said first axle torque request is positive, said DATSM diagnoses said fault when said redundant axle torque request is less than a predetermined deceleration torque that is less than zero. 
     
     
       9. The engine control system of  claim 1  wherein, when said first axle torque request is positive, said DATSM diagnoses said fault when said redundant axle torque request is less than a difference between a redundant axle torque request and a magnitude of a predetermined deceleration torque offset. 
     
     
       10. A method comprising:
 determining a pedal torque request based on minimum and maximum scaling torques and a torque scalar; 
 determining a raw driver torque request; 
 selectively shaping the raw driver torque request into a final driver torque request; 
 converting said final driver torque request into a first axle torque request; and 
 selectively diagnosing a fault in said first axle torque request based on a minimum engine torque, said minimum scaling torque, a first comparison of said final driver torque request and a redundant final driver torque request, and a second comparison of said first axle torque request and a redundant axle torque request. 
 
     
     
       11. The method of  claim 10 , further comprising diagnosing said fault when said minimum scaling torque is one of greater than a predetermined maximum torque limit and less than a predetermined minimum torque limit. 
     
     
       12. The method of  claim 11 , further comprising diagnosing said fault when said minimum torque is one of greater than said maximum torque limit and less than said predetermined minimum torque limit. 
     
     
       13. The method of  claim 10 , further comprising diagnosing said fault when said final driver torque request is one of greater than and less than said redundant final driver torque request. 
     
     
       14. The method of  claim 10 , further comprising setting said redundant final driver torque request equal to one of said final driver torque request and a redundant raw driver torque request before said first comparison is performed. 
     
     
       15. The method of  claim 10 , further comprising limiting a rate of shaping of said final driver torque request toward said pedal torque request. 
     
     
       16. The method of  claim 10 , further comprising diagnosing said fault when said redundant axle torque request is greater than a sum of said first axle torque request and a predetermined acceleration torque. 
     
     
       17. The method of  claim 10 , further comprising diagnosing said fault when said first axle torque request is positive and when said redundant axle torque request is less than a predetermined deceleration torque that is less than zero. 
     
     
       18. The method of  claim 10 , further comprising diagnosing said fault when said first axle torque request is positive and when said redundant axle torque request is less than a difference between a redundant axle torque request and a magnitude of a predetermined deceleration torque offset.